Article coated with intumescent undercoat of a synthetic resin, inorganic foam forming agent and carbon forming agent and water-insoluble organic solvent based resin overcoat

ABSTRACT

An article having a fire resistant coating which includes an intumescent undercoat of an aqueous mixture of a synthetic resin, an inorganic foam forming agent and a carbon forming agent. Over the intumescent undercoat there is applied a nonflammable waterinsoluble organic solvent based resin. This latter overcoat is essentially incompatible with the intumescent undercoat composition.

United States Patent Moran et a1.

[451 May 16, 1972 [541 ARTICLE COATED WITH William F. Moran,Randallstown; Lucian C. Kyrias, Baltimore, both of Md.

Assignee: Beatrice Foods C0., Chicago, 111.

Filed: Sept. 9, 1970 Appl. No.: 70,725

Inventors:

Related US. Application Data Continuation of Ser. No. 680,343, Nov. 3,1967, abandoned.

U.S.Cl ..117/76P, 117/72, 117/136, 260/6, 260/7, 260/75, 260/8, 260/172,260/173, 260/17.4

Int. Cl. ..B44d l/14,C08g37/32,C08g51/14 Field of Search ..260/8, 6,7.5; 117/76, 7.5, 117/72,137, 136

[56] References Cited UNlTED STATES PATENTS 1,852,998 4/1932 Ellis..117/137 2,452,054 10/1948 Jones et a1. ..117/137 2,523,626 9/1950Jones et a1. ..260/6 2,600,455 6/1952 Wilson et a1. .....260/6 2,606,1318/1952 Aiken et a1. ....1 17/137 2,813,046 11/1957 Lauring ..117/1372,881,088 4/1959 Schulenburg ..260/8 2,938,937 5/1960 Shenk .117/1373,312,565 4/1967 Rayner et a1 ..117/72 OTHER PUBLICATIONS PaintAdditives," Preuss, Metal Finishing, Mar. 1967. pg. 56- 59.

Primary Examiner-William H. Short Assistant ExaminerEdward WoodberryAttorney-Cushman, Darby & Cushman [5 7] ABSTRACT An article having afire resistant coating which includes an intumescent undercoat of anaqueous mixture of a synthetic resin, an inorganic foam forming agentand a carbon forming agent, Over the intumescent undercoat there isapplied a nonflammable water-insoluble organic solvent based resin. Thislatter overcoat is essentially incompatible with the intumescentundercoat composition.

6 Claims, No Drawings ARTICLE COATED WITH INTUMESCENT UNDERCOAT OF ASYNTHETIC RESIN, INORGANIC FOAM FORMING AGENT AND CARBON FORMING AGENTAND WATER- INSOLUBLE ORGANIC SOLVENT BASED RESIN OVERCOAT This is acontinuation of application Serial No. 680,343 filed Nov. 3, 1967, nowabandoned.

This invention relates to an improved fire retarding coating system andmore particularly to a coating system which ineludes as an undercoat tobe applied to a surface to be protected, an intumescent coatingcomposition and as an overcoat to be applied to said intumescent coatingcomposition, a nonflammable coating material which is essentiallyincompatible with said intumescent coating composition.

l-leretofore, efforts directed to improve the resistance of organiccoatings to fire have resulted in adding intumescing agents theretosince one of the most important characteristics of a fire retardantorganic coating is intumescence. This is the property of swelling orpuffing when exposed to extreme heat or a flame. Gases are given offwhen the organic coating is exposed to the heat or flame and are trappedby the carbonaceous structure to form a cellular insulating layerbetween the fire, flame or extreme heat and the substrate. It has beenfound, however, that organic coatings containing water dispersiblelatices together with intumescing agents, while initially providingsatisfactory fire retardant properties lose their effectiveness onscrubbing or washing. Efforts to provide a washable fire retardantcoating composition have resulted, for instance, in a two coat systemwhich requires that the overcoat and undercoat be compatible Such asystem has been found disadvantageous because of the tendency of theovercoat, being compatible with the undercoat, to soften the latter orto become integral therewith, thereby permitting migration of theintumescing agents to the overcoat when the same is applied to theundercoat. Consequently, on washing or scrubbing the overcoat, a portionof the intumescing agents are removed from the coating system.

It has now been found that these disadvantages can be avoided and animproved fire retarding coating system produced when the undercoat andovercoat compositions are essentially incompatible.

It is therefore an object of the present invention to provide animproved fire protective or retardant coating system essentiallycomposed of an intumescent coating composition applied to a substrateand an essentially nonflammable coating composition applied to theintumescent coating composition, said coating compositions beingmutually substantially incompatible.

Another object of the present invention is to provide a fire retardantcoating system wherein the overcoat composition is washable without anyappreciable loss of fire retardant properties of the coating system andwhich can provide a semigloss or high gloss finish, as desired.

With the foregoing objects in view, as well as others which will becomeapparent as the description proceeds, the invention consists in a twocoat fire protective composition system in which the intumescent coatingcomposition applied to the substrate is an aqueous mixture of asynthetic resin having incorporated therein an inorganic foam formingagent and a carbon forming agent.

Synthetic resins which can be usefully employed in the undercoatcomposition of the present invention include urea formaldehyde resins,polyvinyl chloride, neoprene, polyvinyl acetate, polyacrylate,polystyrene, copolymers of styrene and butadiene, copolymers ofvinylidene chloride and acrylonitrile, copolymers of butadiene andacrylonitrile, copolymers of styrene and acrylonitrile and theirmixtures. The synthetic resin can be present in the aqueous mixture inamounts ranging from 5 to 20, preferably to 15, based on the totalweight of the mixture.

The inorganic foam forming agent present in the aqueous mixturecomprising the undercoat composition can include, for instance,mono-ammonium phosphate, diammonium phosphate, phosphoric acid, ammoniumsulfate, sulfamic acid,

ammonium sulfamate, ammonium bromide, sodium tungstate, sodium borate,boric acid, carbamic phosphoric acid, vermiculite and their mixtures.The foam forming agent is present in the aqueous mixture in amountsranging from 25 to 40, preferably 25 to 35 weight percent of the totalmixture.

Conventional carbon forming agents suitably used in the aqueous mixtureinclude, for instance, casein, starch, modified starch, isano oil, gumtragacanth, gum arabic, Irish moss and the like, as well as theirmixtures. The carbon forming agent is present in amounts between about 5to 20 and preferably 10 to 20 weight percent, based on the totalmixture.

In addition to the above components, the aqueous mixture can alsoinclude diluents or inert fillers, pigments, wetting agents,emulsifiers, plasticizers and the like.

The nonflammable coating applied to the intumescent coating compositionis an organic solvent based chlorinated rubber or synthetic resin and isessentially incompatible with the intumescent undercoating composition.Usefully employed are the medium-oil alkyds, the long-oil alkyds and thevery long oil alkyds. Preferably halogenated alkyds, especiallychlorinated alkyds percent) are employed in amounts ranging from 15 to35 of the total overcoat composition. The alkyds can have incorporatedtherein polyhydric alcohols such as glycerol, pentaerythritol,di-pentaerythritol and the like to increase the viscosity of thecomposition as well as to improve its drying characteristics.Additionally, the inclusion of polyhydric alcohols in the overcoatingcomposition improves its water resistance, gloss and gloss retentioncharacteristics and the composition shows balanced hardness andflexibility properties. Polyhydric alcohols can be present in amounts ofabout 2 to 6 weight percent of the total composition.

Blending agents such as urea and melamine resins as well as chlorinatedrubbers which aid in improving color and color retention, durability,gloss and gloss retention characteristics can also be included in theovercoat composition and generally will be present, when used, inamounts of about 15 to 35 percent by weight of the total.

Commercial driers and metallic soaps are also incorporated into thealkyd resin overcoat composition and can include, for instance, Al, Ba,Ca, Cu, Co, Fe, Pb, Li, Mg, Mn, Zn and Fn stearates, naphthenates,tallates, 2-ethylhexoates, linoleates, palmitates and oleates.Preferably employed is aluminum stearate. The driers are generallypresent in amounts of about 1 to 2 weight percent of the total.

Also included in the overcoating composi-tion are hydrocarbon thinnersincluding mineral spirits, a highly refined distillate of petroleumboiling in the range of about 300 to 385 F as well as pigments and inertfillers in conventionally employed amounts. Such pigment materials andother solid components include titanium dioxide, antimony oxide, sodiummetaphosphate, calcium carbonate, antimony silico oxide, zinc oxide andthe like. Ordinarily the pigment will be present in amounts ranging fromabout 35 to weight percent of the total overcoating composition.

The fire retardant surface coating system of this invention can beapplied to surfaces that are inherently flammable such as paper,cardboard, wood, fibrous wall board and the like as well as tononflammable surfaces such as metal, plasterboard and similar materials.The undercoat and overcoat composition can be applied by brush,spraying, rolling or the like, each coat having a thickness up to about3 to 4 mils or greater if desired. Multiple coats of each coatingcomposition can be applied, as desired. Generally the overcoatcomposition is not applied to the intumescent undercoat compositionuntil the latter has thoroughly dried, which in most instances will beabout 1 to 2 hours after its application to the substrate to beprotected. While the overcoat composition can be applied in variousthicknesses, it has been found that ordinarily l to 2 mils is sufficientto seal the intumescent gases produced in the undercoat composition.Surprisingly, it has also been found that the organic solvent basedovercoat has sufficient adhesion to the aqueous based undercoat toprevent delamination but remain a film over the intumescent undercoatwhen the the present invention but are not to be interpreted in alimiting sense Intumescent Undercoat Compositions:

EXAMPLE I Parts by weight Potassium tripolyphosphate 3 Melamine 30Ammonium Polyphosphate 260 Dipentaerythritol 75 Chlorinated Parafi'in 40Polyvinyl Acetate Emulsion 220 Water and Wetting Agents 400 EXAMPLE [IWater I52 Starch 3 Urea l Urea Formaldehyde 100%) 20 Titanium Dioxide100 Calcium Carbonate 25 Mono Ammonium Phosphate 90 Styrene-ButadieneLatex 3 Wetting Agents and Thickeners 72 EXAMPLE Ill Triethyl Phosphate2O Urea Formaldehyde Resin l2 Titanium Dioxide 7 Water Polyvinyl AcetateHomopolymer 62 EXAMPLE IV Mono Ammonium Phosphate 75 Pentaerythritol 10Titanium Dioxide 14 Sodium Alginate trace Water 50 Polyvinyl ChlorideHomopolymer l9 Diphenyl Phosphate 3 EXAMPLE V Mono Ammonium Phosphate 60Boric Acid 2 Corn Starch 7 Titanium Dioxide 5 Calcium Carbonate l0 Urea9 Paraforrnaldehyde l5 Styrene-Butadiene Latex l8 Nonflammable OvercoatCompositions:

EXAMPLE Vl Titanium Dioxide Parts by weight Melamine 20 Titanium Dioxidel0 Halogenated Alkyd Resin 40 Mineral Spirits or other Thinner 53 Driers1 EXAMPLE VIII Calcium Carbonate 20 Titanium Dioxide 20 Antimony Oxide10 Aluminum Stearate 2 Halogenated Alkyd 45 Thinners l5 Driers 2 EXAMPLEIX Titanium Dioxide 23 Calcium Carbonate 34 Antimony Silico Oxide 10Aluminum Stearate 2 Chlorinated Alkyd 38 Chlorinated Paraffin 7 Thinnersl8 Driers 1 We claim:

1. A method for protecting an article against fire which comprisesapplying to the surface of said article an undercoating materialconsisting essentially of an aqueous mixture of a synthetic resinconsisting essentially of a member selected from the group consisting ofurea-formaldehyde, polyvinyl chloride, neoprene, polyvinyl acetate,polyacrylate, polystyrene, copolymer of styrene and butadiene, copolymerof vinylidene chloride and acrylonitrile, copolymer of butadiene andacrylonitrile, copolymer of styrene and acrylonitrile and theirmixtures, said synthetic resin being present in amounts of 5-20 weightpercent of said mixture, an inorganic foam forming agent consistingessentially of a member selected from the group consisting ofmono-ammonium phosphate, di-ammonium phosphate, phosphoric acid,ammonium sulfate, sulfamic acid, ammonium sulfamate, ammonium bromide,sodium tungstate, sodium borate, boric acid, carbamic phosphoric acid,vermiculite and their mixtures, said foam forming agent being present inamounts of 25 to 40 weight percent of said mixture and a carbon formingagent consisting essentially of a member selected from the groupconsisting of casein, starch, isano oil, gum tragacanth, gum arabic,lrish moss and their mixtures, said carbon forming agent being presentin amounts of 520 weight percent of said mixture and applying over saidundercoating material a waterinsoluble overcoating material consistingessentially of an organic solvent based resin which is essentiallyincompatible with said undercoating material, said organic solvent basedresin consisting essentially of a member selected from the groupconsisting of chlorinated rubber and alkyd resin selected from the groupconsisting of medium-oil alkyd resin, long-oil alkyd resin, very longoil alkyd resin and chlorinated alkyd resin containing percent chlorine,said organic solvent based resin being present in amounts of 15-35weight percent of said overcoating material.

2. The method of claim 1 wherein mineral spirits or a refined distillateof petroleum boiling in the range of about 300-385F. is admixed withsaid organic based resin.

3. The method of claim 1 wherein a pigment is present in saidovercoating material in amounts of about 35 to weight percent of saidovercoating material.

4. An article having thereon a fire resistant intumescent undercoatformed from an undercoating material comprising an aqueous mixture of asynthetic resin consisting essentially of a member selected from thegroup consisting of urea formaldehyde, polyvinyl chloride, neoprene,polyvinyl acetate, polyacrylate, polystyrene, copolymer of styrene andbutadiene, copolymer of vinylidene chloride and acrylonitrile, copolymerof butadiene and acrylonitrile, copolymer of styrene and acrylonitrileand their mixtures, said synthetic resin being present in amounts of 5weight percent of said mixture, an inorganic foam forming agentconsisting essentially of a member selected from the group consisting ofmono-ammonium phosphate, di-ammonium phosphate, phosphoric acid,ammonium sulfate, sulfamic acid, sodium borate, boric acid, carbamicphosphoric acid, vermiculite and their mixtures, said foam forming agentbeing present in amounts of to 40 weight percent of said mixture and acarbon forming agent consisting essentially of a member selected fromthe group consisting of casein, starch, isano oil, gum tragacanth, gumarabic, Irish moss and their mixtures, said carbon forming agent beingpresent in amounts of 5 20 weight percent of said mixture, and anon-flammable, waterinsoluble overcoat applied over said undercoat saidwater-insoluble overcoat formed from an undercoating material consistingessentially of an organic solvent based resin which is essentiallyincompatible with said undercoat, said organic solvent based resinconsisting essentially of a member selected from the group consisting ofchlorinated rubber and alkyd resin selected from the group consisting ofmedium-oil alkyd resin, long-oil alkyd resin, very long oil alkyd resinand chlorinated alkyd resin containing 60 percent chlorine, said organicsolvent based resin being present in amounts of 15 35 weight percent ofsaid overcoating material.

5. The article in claim 4 wherein the resin in the overcoat is an alkydresin or chlorinated rubber.

6. The article in claim 5 wherein the alkyd resin is a halogenated alkydresin.

2. The method of claim 1 wherein mineral spirits or a refined distillateof petroleum boiling in the range of about 300*-385* F. is admixed withsaid organic based resin.
 3. The method of claim 1 wherein a pigment ispresent in said overcoating material in amounts of about 35 to 65 weightpercent of said overcoating material.
 4. An article having thereon afire resistant intumescent undercoat formed from an undercoatingmaterial comprising an aqueous mixture of a synthetic resin consistingessentially of a member selected from the group consisting of ureaformaldehyde, polyvinyl chloride, neoprene, polyvinyl acetate,polyacrylate, polystyrene, copolymer of styrene and butadiene, copolymerof vinylidene chloride and acrylonitrile, copolymer of butadiene andacrylonitrile, copolymer of styrene and acrylonitrile and theIrmixtures, said synthetic resin being present in amounts of 5 - 20 weightpercent of said mixture, an inorganic foam forming agent consistingessentially of a member selected from the group consisting ofmono-ammonium phosphate, di-ammonium phosphate, phosphoric acid,ammonium sulfate, sulfamic acid, sodium borate, boric acid, carbamicphosphoric acid, vermiculite and their mixtures, said foam forming agentbeing present in amounts of 25 to 40 weight percent of said mixture anda carbon forming agent consisting essentially of a member selected fromthe group consisting of casein, starch, isano oil, gum tragacanth, gumarabic, Irish moss and their mixtures, said carbon forming agent beingpresent in amounts of 5 - 20 weight percent of said mixture, and anon-flammable, water-insoluble overcoat applied over said undercoat saidwater-insoluble overcoat formed from an undercoating material consistingessentially of an organic solvent based resin which is essentiallyincompatible with said undercoat, said organic solvent based resinconsisting essentially of a member selected from the group consisting ofchlorinated rubber and alkyd resin selected from the group consisting ofmedium-oil alkyd resin, long-oil alkyd resin, very long oil alkyd resinand chlorinated alkyd resin containing 60 percent chlorine, said organicsolvent based resin being present in amounts of 15 - 35 weight percentof said overcoating material.
 5. The article in claim 4 wherein theresin in the overcoat is an alkyd resin or chlorinated rubber.
 6. Thearticle in claim 5 wherein the alkyd resin is a halogenated alkyd resin.